In the 1400s, China owned the greatest seagoing fleet in the world, up to 3,500 ships at its peak. (The U.S. Navy today has only 430). Some of them were five times the size of the ships being built in Europe at the time.

The space company said in a statement that the two individuals have “already paid a significant deposit” to do a Moon mission. Initial training, along with health and fitness tests, are set to occur later this year, SpaceX continued.